And really, I have run into problems with this because when I do bring it up I’m probably not as direct as people need me to be. It *feels* like I’m being direct; e.g. I might say, “I take issue with _____.” I’m starting to think people actually need me to say “I find ____ offensive.” To me, not only is that the same thing- but saying it like that is actually offensive in its own way. It’s asserting that something is ‘objectively’ offensive. There are extremely few things I believe to be ‘objectively’ offensive- and calling something which I recognize might only be offensive to me ‘objectively’ offensive is treating someone like they are stupid/impressionable enough to swallow it whole.
So in short: I will let someone know I have a problem with something if I get the feeling they would rather know than have me distance them. But if they aren’t especially close to me (and I get the feeling they’d just as soon I distance them than give them some ‘rule’ to adhere to which they likely won’t understand), then I just distance them instead.
eta: I'm not sure exactly what you mean by "friendship with considerable time investment"- because that doesn't necessarily mean there's a close bond. There are many people with whom I've been friends for a long time, but I don't feel especially close to.